The present invention relates to paving vehicles, and more particularly, to paving vehicles having screeds and devices, such as augers, for spreading paving material forwardly of the screeds.
Referring to FIG. 1, a paver vehicle or xe2x80x9cpaverxe2x80x9d 1 generally includes a paver chassis or tractor 2 and a screed 3 for leveling paving material and connected with the chassis 2 so as to be pulled from the rear end 2b thereof. A storage bin or hopper 4 for holding a supply of paving material P is typically mounted on the front end 2a of the chassis 2 and a conveyor 6, which extends longitudinally on the chassis 2, transports paving material P from the hopper 4 to the rear end 2b of the chassis 2. The material P falls off the chassis rear end 2b and deposits onto a base surface 7 being paved, such as a roadbed.
An auger 8 is generally disposed between the rear end 2b of the chassis 2 and the screed 3 and functions to spread deposited material laterally across the front 3a of the screed 3 so as to form a head of material H. The screed 3 is pulled into the head of material H as the paver 1 travels upon the base surface 7 such that portions of the material head H flows under the screed 3 and is leveled, and preferably also compressed, into a mat of material M having a generally uniform thickness. Typically, the paving material P, such as asphalt or cement, is formed of an aggregate of material particles of various sizes and there are generally substantial size differences between the larger and smaller particles.
One problem with such known pavers arises due to the above-noted size differences between the material particles of the head of material H. Larger particles, particularly those particles at the top of the material head H, tend to fall from the head of material H as the paving material P is first deposited and then spread by the auger 8, such that the head H xe2x80x9csegregatesxe2x80x9d or separates into regions of larger particles and smaller particles. The segregation of material particles is increased by the forward movement of the material head H, the head H being pushed along the base surface 7 by the screed 3, such that larger particles tend to accumulate forwardly of the remainder of the head H. With such material segregation, the portions of the material head H that are leveled tend to have a greater than intended proportion of smaller or finer particles, causing the formed material mat M to have less strength than desired.
Therefore, it would be desirable to provide a device for a paver to prevent the segregation of material particles in a head of paving material.